X-ray camera



17, 1950 v R. J. STAVA 2,526,094 X-RAY" CMERA Filed Sept. 24, 1947 3 Sheets-Sheet 1 IN VEN TOR. ROBERT J. STAVA ATTORNEYS R. J. STAVA X-RAY CAMERA Oct. 17, 1950 Filed Sept. 24, 1947 3 Sheets-Sheet 2 IN VEN TOR. ROBERT J. STAVA aw 112w ATTORNEYS Oct. 17, 1950 R. J. STAVA 2,526,094

' X-RAY CAMERA 3 Sheets-Sheet 3 Filed Sept. 24, 1947 FIG-4 INVENTOR. ROBERT J. STAVA ATTORNEYS Patented Oct. 17, 1 950 7 Robert J. Stava,

, signor'" to Picker ManufacturingiDivisi a corporation oi :Ohuo

Application September24,

4' Claims. I 250-:65)

This invention relates to photographic cameras, suchas are used more particularly for producing negatives on roll film from X-ray'images cast upon a fluorescent screen. Ihe invention has to do with advancementof the film betweensuccessive exposures."

X-rayv photographicapparatus'of the kind here involved is employed for rapidly taking like pictures of a large numberof individuals or patients, such as where: all the employees in an industrial plant are examined in succession some harmful condition or disease. The patients, in turn, step toa standard position between'an X-ray tube and fluorescent screen, whereuponthe operator presses a button to energize the tube and thuscast the-usual shadow image upon the the screen. Sincethe camera is focused upon the screen, the; im'age isreproducedi upon. the? film,

in negative form; .Usually, in such"apparatus; termination of'tlieiexposu're period, by relay or' switch operation, automatically advances the roll film one step, leaving'th'e" apparatus ready :tor? the next, exposure.

However, the shadow imageupon the-fluorescent screen usually persists for a short period, say two or three seconds after the? X-ray' tube circuit'iis opened, duringwhich'period; Whilethe imageis. it" still isstrong enough to affect the dying'away; film.. Consequently, immediate advance of the, film causes fuzziness or'a somewhat blurred image,- with loss of detail and possible obscurity respecting'the particular information soughtbtheexposure;

The present invention has for ltSwCibjeCf/ to provi-rie improved film-feeding or advancing meansJin which, after a starting impulse, actual advancerof' the filmis delayed during ashort interval, of the order of, say, two seconds or $0, 31; periodlong';

enough toperm t the -fi uorescent :image to fade sufficiently to avoid or} prevent blurring; or fuzzi- 1 ness and in ure a sharp deepnegative.

Another object is to -provide.improyedmechanical means for, causing time delayin filmadvance, such means being ofrelatively; simple form, able in operation. and not. likely to .get out of order inservice. v I i 7 I Still another object isltofprovide improved mechanism of the cliaracter. described,.including a yieldable pressure plate. for holding thefrlmin flat form, together with'me'ans for, releasing said plate during film advance, but subject to: the same time delay as the film advancing means.

A further object is to. generally simplify. and improve the mechanism in aimannerto secure clean, sharp negatives free fromiuzziness or blurring and-hence of, high quality.

for evidence of L X-RAY CAME A 7 University Heights, Ohio, as-

X-Ray Corporation Waite 1947, Serial No. 775,863

Further objects of the invention in part are ob- Fig. 4 is'a sectional elevation, on the line 4 -4,

Fig. 1; i v Fig; 5. is a sectional elevation on the line 5+5,

Fig. 4; I

Fig; 6 is a detail'sectional view on the line 6-45,

Fig.:3; and,

Fig; 7 isf'a 'wiring diagra'rn', illustrating somewhatfconventionallythe control circuits.

Referringfir'st to Fig. 2; the X-ray photographic v apparatus here involved com-prises ahollowcamera-body portion or frame it enclosing alight l threaded portion 12 of tightchamber H and" in a which is mounted the usual photographic lens (not shown) capable of iocusing upon the active portion of the film E3 the negative reproduction off-'anX-ra shadowimage cast upon a parent fluorescent screen end of a hood Ma, to which the camera is at tached, allin the usual manner. is designed to employ, for example, '70 mm. imperforated X-ray roll film up to one'hundred feet long mounted to travel up. to four hundred or so exposures per roll. The film spools, pressure plate and some operating parts therefor are mounted in and carried by a detachable film magazine or unit l5, slidabl supr corresponding opening ings together in operative relation,

ported upon guide flanges 66 (Fig.1) of thecamera housing, while the power motor, transmission carried by thehousing. slidrinto place, bymotion fromthe bottom toward thetop in Figs 3 and 4, a windowopening Win the irontwall l aof the film unitiregiste'rs with a film unit casing liesibeneath theoverhanging extended portion 2| of the top plate 2 2,,of-the camera housing H3. A remove ablecover 23, attached to plate 22 provides a supe plementalchamber 24- in which certain mecha-. nism is located. Suitable locksor latches (not shown) releasably holdrth'e camera and film casas will be readily understood.

Within the chamber of the filmunit' are "ro- J tatably and.-removably mounted a f11m supply transl4 mounted at the outer The camera from spool tospool with H Him the rear wall 20 of thehousing-IB, as shownin Fig. 4,,and'a portion" 0t, top-wall l5aof the supports a cros pin spool 36 and a, film take-up spool 3|. The film I3 is led from the supply spool around an idler roller 32, then across the field in flat form in front of a pressure plate 33 to and around a metering roll 34, and then to the take-up spool. Metering roll 34 and take-up spool 3| are both driven by the same mechanism, now to be described.

Within the chamber ll of the camera housing is mounted an electric motor 35 (Fig. 3) the spindle of which, through speed reducing gearing marked generally 35, drives a shaft 37 extending through a supporting plate 38, beyond which said shaft carries a small pinion 39 meshing with a large gear 4!]; on a shaft 4|. Shaft 4| extends through the top wall 2| of the housing into supplemental chamber 24, where it supports an interrupted gear 42 and a cam 43.

Interrupted gear 42 has two diametrically opposite sets of teeth 42a, F g. 6, each set lying opposite or beneath one of the two high lobes 43a of the cam. Between the sets of gear teeth the gear 42 has plain convex circular portions 42b, each lying beneath a low or recessed portion 43b of the cam.

Gear 42 cooperates with and drives a second gear 44 on astub shaft 45, said gear 44 having two sets of gear teeth 44a between which sets are..locatedstop members 441), each having a concave curved surface fitting and cooperating with one of the plain surfaces 42b of gear 42. Shaft 45 also sup orts a large nion 45 meshing with a smaller p nion 41 on a shaft 8, ou na l d in the overhan ing portion of wall 2|, the end of said shaf having cl tch pi s 49 entering recesses in the end of a coup ing member 5!] mounted in the upper wall |5a of the film unit. This coupling adapt d to ent r a cross slot 52 in'the end of the shaft 53 of metering'roll 34 for driving the same.

Pin 49 and their cooperatin recesses in member 53 form anendwise separable drivi g connection between that p rt of the gearing carried by the camera unit and th t carried by the film unit, enab ing the two to be separated when desired. P n 5| and its slot enable the film operating mechanismto be removed from the casing of the film ma azine.

'Shaft 53 is provid d with a pinion 54 which meshes with a ear coaxial ith a se o d gear 55 and coupled to it bv friction material 51, so that drive from gear 55 to gear 56 is through a. yieldin frict on clutch, enabling gear 56 to slip as spool 3| fills up.

Gear 56 d ives a inion 56a which meshe with gear 58on the shaft of s ool 3|. Gears 54 and 58 are of like pitch diameter.

,Referring to Figs; 1 and 5, the pressure plate 331s yieldingly advanced by sprin s 53%0 press the film against those portions of the wall of the When the film take-up'spool this plate serves as a shutter, closing the magazine against light rays.- Plate 33 supports a metal backing member 60 having ears 6| supporting a pin 52 to which is connected one end of an arm'63 on a shaft 64 having a second arm. as pivoted to a link as having through which passes a pin 68 eccentrically mounted on the end of a shaft 69. Pin 68 is normally stationary and serves as a guide to cause endwise motion of link 66 when it is operated, as will appear later.

of a two-armed lever 70 pivoted at H, the second arm abutting the head of an adjustable set screw 12 in a plunger 13 slidably mounted in a bushing in the wall of the camera unit. Said plunger is alined with the end of a push rod 14 mounted in the wall of the film magazine and urged toward plunger 13 by a spring 14a. The opposite end of push rod 14 lies opposite the free end of link 66.

One arm of lever 10 also engages a roller 16a on the end of the operating lever 16 of a normally open switch S4 in the control circuit.

Referring to Fig. 7, the control devices shown are as follows:

T represents a suitable timing device controlled by push button PB and capable of adjustment so that when energized it will close contacts TC andhold them closed during any desired exposure period.

X represents a relay which, when energized, causes operation of the X-ray tube conventionally indicated at 11, Fig. 2.

R! is a relay which, when energized, closes normally open switch SH and also moves the biased double-throw switch SI 2 from the position shown to its opposite position.

R2 is a relay which, when energized; closes normally open switches S2|, S22.

R3 is a relay which, whenenergized, closes normally open switches S3 l, S32.

S4 is a double-throw switch actuated by the cam 43 driven by motor 35.

All parts are shown in the normal positions which they occupy at the beginning of a cycle ready for initiation of an exposure and the production of a negative from the shadow image of a patient located b tween the X-ray tube 7! and fluorescent screen 4.

The roller 15 on lever 10 has dropped off from the high lobe 43a of cam 43, which rotates countel-clockwise in Fig. l. A smooth tooth-free port on 421) of gear 42 .is in-engagement with one 01' the curved stop lugs 44b of the cooperating p nion 44. Thus gear 44 is locked and is nonrotatable, wh ch serves to also lock the metering roll 34 against rotation.

It will be observed that relay R3 is normally energized. In fact this relay is energized all of the time, except during most of the film transport 'or advance interval. It is energized by current'flowing from L1 by way of conductors BI, 82, switch S4 in the position shown, conductor 83 and relay coil R3 to L2. This relay holds switches S3 and S32 closed against their bias to" open position.

Cam 43 is in suchposition that the roller 15 has just dropped off from a high lobe of the cam to a low lobe thereof and switch S4 is in the position shown. 7

Gears 42, 44 constitute a modified Geneva stop mo'vement, their operation including lost motion, with consequent time delay.

Theoperation is as follows:

- Push button PB is ing-device T, which closes switch'TC, thus energizing relay coil RI. produces two effects. I

First, it closes switch S|,|, thus energizing relay X and the X-ray tube Hgwhich it controls, beginning the exposure. Current flow is from L1 by wires BI and. 82, switch S4 in the position shown, conductor 83, switch SH, now closed, relay X and conductor 84 to L2. The exposure continues so long as the relay RI holds S|| closed which keeps relay X energized.

The second effect is to move switch S|2 from..

the position shown to its second position. This pressed, energizing the tim Energiz ation of this coil I energizes relay R2,

plain portion 42b of total 180. of movement-o by currentfifiowing 'from"L1 by conductor 8|; switch sfilg now' closed, switch SIZ, and relay R2 to conductor: 85, to Closing of relay RZtcloses normally open switches The closing of switch taining circuit for relay S2! provides a mainductor 8|, through switches 'S3 2-*andi"S21 and relay coil R2 to "conductor 85: and toL'L.

Theexposure continues" until: finally timer T automatically opens thecontact'sl TC;- thus: deenergizing'relay coil BL. This in turn causes opening of switch SI l thus deener gizing relayX and the -X-ray .tube which it controls. At' the same time switch SIZ, which has been maintaining a circuit to coil :RZyreturn's to its original position, as. the result of the deenergization of coil RI. Thereupon, a motor circuit is com pleted from L1 by conductor 8t, switch S32, switch Sl2, switches S22 and 63!, conductor-86, and motor 35 to conductor 85' andto L2:

The mechanism is'what is termed a two-cycle mechanism, in the sense that one complete rotation of shaft 41, interrupted gear 42 and the cam; 43 produce two complete cycles-o advance of the film; When the motor wstartsgywhile it rotates shaft. 41,, that rotation at. first is ineffective upon any other parts, because the low lobeaof the cam 43 is trav l ing past ther'oller 1 5, withouteffect upon arm and a smoother gear- 42 0f the interrupted gear mechanism or Geneva stop move'mentis traveling, with lost motion, past a stop lug 441) which is therefore held stationary, so that shaft 45 does not turn. Approximately '75? of, the

f' shaft 45 are devoted bunting to" a period to intentional time delay, am of the order of one and seconds, for the purpose of enabling the image on the fluorescent screen to fadeor. die away while the film is out liability ofblurring or obscuring the .negative image being produced on the fil After approximately 75 of rotation, the next high lobe 43a of the cam becomes effective upon roller and turns lever 10 clockwise in Fig. l. Lever motion is transmitted through plunger 13 to push rod 14, which in turn communicates the motion to the end of link 66. This link slides to the left in Fig. 1, its motion being guided by the pin 68 and slot 61, Motion of thelink is communicated through lever arm 65, shaft 54 and arm 53 to the pressure plate, which is moved bodily to the left in Fig. 1 against the pressure of springs 59, thus relieving the film of pressure, ready for advance.

Simultaneously the interrupted or Geneva smooth portion 42b of the gear 42 passes beyond the stop lug 42b and the teeth 42a engage teeth44a of pinion 44. This'pinion begins to rotate, turns shaft 45 and through and 58 drives the take-up spool 31. Shaft 59, carrying the metering roll 34 is also driven. Thus continued operation of the motor, by actuation of the metering roll and take-up spool, advances the film one step.

a h'alf to two or three I held stationary, and thus with-' gears 45,41, 54,55, 56, 51 a fit turn accordingly. When this new position is reached, the roller 15 drops off from the'high lobe of the cam, permits switch S l to return to the motor, andits original position and stop releases the pressure of plunger 14 on'link 66 and permits the pressure plate springs to again become effective upon it. At the same time the second plain portion of the gear 42 enters the curved recess of the next stop lug 44b and'locks the driving gearing, thus completing onecycle' of film advance operations. All. parts are" now ready for the next exposure and film advance.

The slip connection between the pinions permits take-up roller metering roller as the film builds up on the take-up spool as will be readily understood.

It' should also be noted that the cam lobes on cam 43 and the curved smooth portions of the interrupted gears 42, 44 are 50 disposed or timed, with relation to each other, in the assembled mechanism that during the cycle of operations the'pre'ssure plate backs away from the film before the film begins toadvance, and film advance stops before the pressure plate is returned or ad'- vances toits holding positiomthereby avoiding filmabrasion. 1

The mechanism described is ofsimple con-v struction, involving but fewparts not likely to get out of order and yet insures sufficient delay in actual film advance motion to avoid any possibility of a blurred or obscured negative image. The negatives produced therefore are sharp and clear and capable ofeas'y'and correctinterpretation. i

Other advantages ofthe invention will be apparent to those skilled in the art.

. upon energization of said motor,

contemporaneously with'the two operations predetermined exposure What I claim is:

1. Film advancing means for an X-ray camera of that type in which X-rays are directed from an X-ray tube through an object upon a fluorescent screen from which the rays are transmitted to an exposed area of-a multiple exposure roll film a loop of which is led around a film advancing shaft, comprisin an electric motor, timing means for energizing the X-ray tube during a predetermined exposure interval, means controlled by said timing means for energizing said motor at the conclusion of the exposure interval, and operating mechanism connecting said motor and shaft, said operating mechanism including an interrupted gear movement so arranged that, initiation of rotation of the driven side of said gear movement and of said shaft is delayed pending the lapse of a time interval and consequent material fading of the fluorescent image.

' 2. Film advancing means for an X-ray camera ofthat. type'in which X-rays are directed from an X-ray tube through an object upon a fluorescent screen from which the rays are transmitted to an exposed area of l a multiple exposure roll film a loop of which is led 'around'a film advancing shaft, comprising an electric motor, timing means for energizing the X-ray tube during a interval, means confor energizing said trolled by said timing means motor at the conclusion of the exposure'interval, operating mechanism connecting said motor and shaft, said operating mechanism including an interrupted 'gear movement so arranged that upon-energization of said motor initiation of rotation of the driven side of said gear movement and of said shaft is' delayed pending th'e'lapse of a time interval and consequent material fadingof the fluorescent image, andmeans operated by 55, 55 3| to lag behind the,

said motor when rotation of the driven side of the gear movement has concluded for deenergizing its own energizing means to stop film advance beyond a definite amount.-

3. Film advancing means for an X-ray camera of that type in which X-rays are directed from an X-ray tube through an object upon a fluorescent screen from which the rays are transmitted ing shaft, comprising an electric motor, timing means for energizin the X-ray tube during a predetermined exposure interval including exposure producing and exposure ending operations, means controlled by said timing means for energizing said motor at the conclusion of the exposure interval, operating mechanism connecting said motor and shaft including a pinion having teeth interrupted by a stop member having a concave arcuate exterior face, said pinion operatively connected with said shaft, said mechanism including a gear having teeth adapted to mesh with said pinion teeth and interrupted by a convex arcuate face adapted to nest with said arcuate face of said pinion, said-gear operatively connected with said motor, meansstopping said motor approximately when said arcuate faces begin to register, and means for energizing said motor concurrently with the termination of an X-ray exposure, whereby said film is not advanced by rotation of said shaft until said arcuate face of said gear completely passes said stop member thereby preventing blurring of the image on said film due to persistence of the fluorescent image on said screen after exposure termination.

4. The combination of claim 3 including a camhaving a high zone coaxial with said gear teeth and having a low'zone coaxial with said gear arcuate face, first and second electrical energizing circuits for said motor includin switch means having first and second'positions for causing closing of said first and second circuits respectively, follower means between said cam and said switch means for moving the latter to first and second circuit closing positions respectively said first motor as said follower engages said low and high cam zones, means for disabling said first motor energizing circuit responsive to said timing means exposure producing operation, means for enabling energizing circuit responsive second circuit closing position, whereby said second circuit operates said motor until said cam means causes movement of said switch means out of second circuit closing position back to first circuit closing position.

ROBERT J. STAVA.

REFERENCES CITED v The following references are of record in the file of this patent:

UNITED STATES PATENTS 557,050 Great Britain q. Nov. 2, 1943 

